This invention relates to a tamperproof housing assembly which encloses one or more watt-hour meters and associated overload protected switch means and which can be installed on an existing standard panelboard chassis.
Due to the ever increasing cost of electrical energy, increased emphasis has been placed on the conservation of energy. One aspect of the conservation of energy has been to increase the emphasis on accountability for users of electrical energy. This emphasis has the double purpose of making the users aware of their actual consumption of energy and to require them to actually pay for all of their consumption. In many existing large buildings and shopping centers with multiple tenants, it has not been uncommon that the individual tenants were not separately metered for the electricity they used. Instead, the tenants have often been charged for electricity on a proportional basis at a rate based on the square footage of the space they occupy.
Installing individual meters for each tenant in multiple occupancy buildings and shopping centers without completely reconstructing the electrical supply has not always been feasible. The provision of separate watt-hour meters for each tenant has also required separate switches and overload protection arrangements. The connection of these units to existing panelboard chassis containing bus bars which provide low voltage, high ampere service has presented problems. Not the least of these problems is the lack of space within the typical existing panelboard chassis to provide meter sockets closely adjacent the bus bars and the overload protection and switches which are necessarily associated with each meter socket. The public utilities generally require that the meter be located as close to the bus bars as possible and ahead of the user's switch and overload protection arrangement, to prevent theft of electricity, an ever increasing problem in these days of high energy costs.
The typical existing panelboard chassis for polyphase, low voltage, high amperage service has three bus bars that are symmetrically located relative to the center of the panelboard chassis as shown in FIGS. 3, 6 and 7 of the drawings. The typical panelboard chassis is only slightly wider than the array of these three bus bars, as is also shown in the previously mentioned drawings. Thus, a suitable tamper-prevention housing assembly must mount on the panelboard chassis without extending substantially beyond the lateral confines of the panelboard assembly. The polyphase meter sockets, which cannot be centered over the three bus bars because of space restrictions, must be connectable to the bus bars in their proper phase relation. Because of the high amperage which flows through the meter connections in this type of service, rigid bus connectors should be provided between the bus bars and the polyphase meter sockets. These rigid bus connectors must fit into the limited space between the bus bars and the polyphase meter sockets. Whether a single meter socket is provided, as shown in FIGS. 1-4 of the drawings, or a pair of meter sockets are located side-by-side, as shown in FIGS. 5-10 of the drawings, the meter sockets cannot be located directly over the bus bars but must be offset to one side of the panelboard chassis.